Success Rates of Combined Phacotrabeculectomies Versus Separately Performed Procedures

This month’s installment of the “Peer Review” column addresses the decision to combine phacoemulsification and trabeculectomy, as a preamble to the August edition of Cataract & Refractive Surgery Today, which will include a discussion of the most current trends in the management of coexisting cataracts and glaucoma. As always, please keep in mind that the peer-reviewed literature frequently lags behind current trends and practices. Although phacoemulsification and trabeculectomy have often been performed together during the past 25 years, it remains controversial whether a combined procedure or the separated components yield the best long-term control of IOP. In 1959, Epstein proposed that proinflammatory proteins are present in the aqueous of filtering blebs.1 The exact mediators were identified by Freedman and Goddard in 2008.2 When pressure rises during the hypertensive phase after trabeculectomy, elevated levels of TGF ß and PGE2 are found in the bleb’s aqueous fluid; the resulting effect is a more rapid failure of blebs due to fibrosis. Because both TGF beta and PGE2 are proinflammatory, decreasing their levels lessens inflammation in the bleb’s wall and produces a more permeable bleb.3 Today, more potent topical steroids like Durezol (difluprednate ophthalmic emulsion 0.5%; Sirion Therapeutics) and nonsteroidal anti-inflammatory drugs like Xibrom (bromfenac 0.09%; Ista Pharmaceuticals, Inc.) are available. These newer steroid and nonsteroidal topical medications penetrate the anterior chamber rapidly and provide high bioavailability with minimized dosing regimens. A further consideration is the recent development of adjunctive nonpenetrating procedures such as the implantation of the AquaFlow Collagen Glaucoma Drainage Device (STAAR Surgical Company, Monrovia, CA) or canaloplasty with the iTrack 250A Microcatheter (iScience Interventional, Menlo Park, CA), which require a two-site approach. At this year’s American Society of Cataract and Refractive Surgery Symposium in Boston, Marlene Moster, MD, advocated that cataract surgery in less advanced cases of glaucoma (ie, patients on one or two medications with minimal field loss) may be combined with endoscopic cyclophotocoagulation, canaloplasty, or ab interno trabeculotomy (Trabectome; NeoMedix Corporation, Tustin, CA). She reserves filtering surgery for more complicated cases or, if needed, in eyes for which the aforementioned modalities fail. I hope you enjoy this installment of “Peer Review,” and I encourage you to seek out and review the articles in their entirety at your convenience. —Mitchell C. Shultz, MD, section editor Success Rates of Combined Phacotrabeculectomies Versus Separately Performed Procedures